A quiz built from the topics you keep getting wrong, taken from your own notes. Not a generic question bank, and not something a free chatbot can do, because it needs your history.
Lecture notes, a chapter, your homework, or a past paper. The drill is built from this and from the topics you have failed before.
Nothing is published. It is used for your drill and stored in your own account only.
Free accounts get 2 drills a month. Pro gets 40, plus drills on every weak topic rather than one.
These are the topics where you said you were lost. They are stored in your StudyTools account, so the next drill starts where this one finished.